Your are the senior in the shift and your junior comes to you with this ECG as he is not feeling comfortable about it , patient otherwise vitally stable.
Q1: Are you worried and what is your findings?
Q2: What are the common list of drugs that cause this ,and what is the mechanism?
Don't Overlook Cont'
Thanks all for the the excellent comments
Diagnosis : Prolong QTc interval, almost 600
Mechanism :Medications in the K+ efflux blocker category block the outward flow of K+ from intracellular to extracellular spaces. Blockade of the outward K+ currents may prolong the cardiac cycle action potential
The primary electrocardiographic manifestation is QT interval prolongation (QTc interval greater than 0.45 seconds in men and 0.47 seconds in women). Delay of repolarization causes the myocardial cell to have less charge difference
across its membrane, and result in the activation of the inward depolarization current (early after-depolarization R/T), which is seen on ECG as prominent U waves
This may promote triggered activity, which potentially can progress to re-entry and subsequent polymorphic VT including TdP.
R /T phenomenon going to short episode of TDP
Drugs causing prolong QT is huge:
https://crediblemeds.org/ is a good website to look for each drug risk of causing prolong QT
· Common Drugs includes:
Antipsychotics: e.g Chlorpromazine,Haloperidol, Quetiapine Olanzapine, droperidol have been black boxed and withdrawn from market in the past due to prolong QT
Antiarrhythmics
- Type IA( e.g Quinidine ,Procainamide
-Type IC antiarrhythmics ( e.g Flecainide)
-Class III antiarrhythmics( e.g Sotalol,Amiodarone)
3.Tricyclic antidepressants ( e.gAmitriptyline,Imipramine)
4.Other antidepressants( e.g Citalopram,Escitalopram ,Venlafaxine)
5.Antihistamines
6.Other (Chloroquine ,Hydroxychloroquine, Quinine ,Macrolides: Erythromycin; Clarithromycin)
Risk factors for torsades de pointes (TdP) among patients treated with medications that prolong QT interval includes:
( female gender, hypokalemia, hypomagnesemia, bradycardia, overdose, drug interactions , digitalis therapy, and background of the patient (preexisting cardiac disease, long QT interval or family history of long QT)
Management :
Immediate withdrawal of the potential cause
Correction of any coexisting medical problems, such as electrolyte abnormalities.
Patients who have newly diagnosed drug-induced prolongation of their QT interval should be considered candidates for admission to a monitored setting.
IV magnesium sulfate is a highly effective and benign intervention to suppress occurrence of dysrhythmias associated with QT interval prolongation, even though it typically does not result in shortening of the QT interval itself .
In patients who have intermittent runs of torsades de pointes not responsive to magnesium therapy, electrical overdrive pacing should be considered.
References :
1. Murphy, N.G; Benowitz, N.L. & Goldschlager, N. (2007). Cardiovascular toxicology, In:
Haddad and Winchester’s Clinical Management of Poisoning and Drug Overdose (4th Ed.),
Shannon, M.W. et al. (Eds.), pp. 133-165, Saunders Elsevier, ISBN 978-0-7216-0693-
4, Philadelphia, USA.
2.https://litfl.com/qt-interval-ecg-library/
3.https://litfl.com/drugs-causing-qt-prolongation/